It is known to fit turbine engine fan blades that are made out of composite material with metal structural reinforcement that extends over the full height of the blade and beyond its leading edge, as described in Document EP 1 908 919, filed in the name of the Applicant. Such reinforcement makes it possible to protect composite blades in the event of the fan impacting against a foreign body, e.g. such as a bird, hail, or indeed grit.
In particular, the metal reinforcement protects the leading edge of a composite blade by avoiding risks of delamination, of fiber rupture, or indeed of damage by loss of cohesion between the fibers and the matrix. In known manner, the reinforcement is made either by being milled out of a block of titanium, which requires numerous finishing operations and complex tooling involving high fabricating costs, or else starting from a preform obtained from a simple metal bar and by performing a succession of forging steps, as described in particular in patent application FR 2 961 866 filed in the name of the Applicant. Nevertheless, the last forging steps are particularly difficult given the presence of undercuts, and as a result there are sometimes uncertainties as to the final dimensions of the reinforcement, so it is appropriate to be able to perform accurate inspection.
Unfortunately, conventional measurement solutions of the three-dimensional measuring machine (TMM) type or of other types making use of contacts for measuring interior and exterior surfaces of the reinforcement are excluded because of the great geometrical variability of the reinforcement (which makes it difficult to automate a measurement path), and in particular because of the small thickness at certain locations of the reinforcement (which involves a major risk of deforming the part under the sensing force) and because of the inaccessibility of the bottom of the concave reinforcing part, which makes it necessary to use feelers that are long (which involves a major risk of the feeler bending).